This invention relates to a vehicle seat having an adjustable armrest and in particular to a ratchet mechanism for adjusting the armrest.
It is common for vehicle seats to include a reclining feature to enable the angle of the seat back to be varied from a generally upright position to a rearwardly reclined position within a given adjustment range. In addition, in two-door motor vehicles, it is common for the seat back of the front seat to rotate from its upright use position to a forward dump position to improve ingress and egress to and from the rear seat.
Bucket seats, particularly in vans, pick-up trucks and other multi-purpose passenger vehicles, are typically equipped with armrests which extend forward from the seat back on one or both sides of the seat back. The armrest is typically placed in an operative position relative to the seat back so that the armrest extends horizontally forward from the seat back. When the seat back is reclined rearwardly, it is necessary to adjust the angular position of the armrest relative to the seat back to maintain the armrest in a horizontal position. In addition, it is also desirable for the armrest to rotate upward to a stowed position, generally parallel with the seat back. This provides easier access to the seat itself and also, when the seat back is dumped forward, avoids unwanted contact between the armrest and other vehicle interior components.
Various mechanisms have been developed to provide an adjustable armrests. However, the addition of an adjustment mechanism can make the assembly of the seat more difficult. The adjustment mechanism typically requires mechanical interaction between the armrest and the seat back. This interaction makes it difficult to provide a fully trimmed seat back and a fully trimmed armrest which can be simply joined together.
Accordingly, it is an object of the present invention to provide an adjustable armrest for a seat back which can be fully trimmed prior to attachment of the armrest to the seat back.
It is a further object of the present invention to provide an armrest which can be easily attached to a seat back and removed from the seat back without requiring opening of the trim cover of either the armrest or the seat back.
The seat assembly of the present invention provides a mounting stud which extends laterally from the seat back. The armrest is provided with a sleeve extending into the armrest forming a bore which is sized to receive the mounting stud of the seat back. The armrest is attached to the seat back by sliding the sleeve over the mounting stud. A circumferential groove is provided in the stud while the sleeve carries a wire spring clip disposed within opposing circumferential slots in the sleeve. The portions of the wire clip in the circumferential slots crosses the sleeve bore forming chords. The chords are seated into the groove in the mounting stud when the armrest sleeve has been moved over the stud to the installed position of the armrest. The groove is positioned axially along the stud to be at the interface between the armrest and the seat back so that a flat tool such as a screw driver can be inserted between the armrest and the seat back to manipulate the spring clip, releasing the clip from the stud, to remove the armrest if needed for service or repair of the seat assembly.
Once installed, the armrest is rotatable about the stud within an adjustable range of use positions and is also rotatable to an upright stowed position parallel to the seat back. In the range of use positions, a ratchet mechanism is provided to prevent downward rotation of the armrest to enable the armrest to support a downward load applied by a seat occupant. The armrest is adjusted upwardly by pulling upward on the armrest. Doing so causes a pawl carried by the armrest to move into engagement with the next tooth of a sector gear fixed to the seat back. A spring holds the pawl in engagement with the teeth of the sector gear. Upon upward movement of the armrest beyond the range of use positions, a release tooth on the sector gear causes the pawl to rotate to an over center position in which the spring holds the pawl in a position disengaged from the teeth, enabling the armrest to rotate downward. Upon reaching the lower end of the adjustment range, a return tooth on the sector gear will engage the pawl and return it back over center so the pawl will engage the sector gear teeth once again.
Further objects, features and advantages of the invention will become apparent from a consideration of the following description and the appended claims when taken in connection with the accompanying drawings.